Quick update as I've been collating video conferencing tools for others as well.
Though Google announced last year that they were closing Google Hangouts, it is still available for consumer use and supports up to 25 people any 10 of which can be on-screen at the same time. Requires a google account. Google now refer to this as "Google Hangouts Classic" to differentiate it from "Google Hangouts Chat" which, despite the name is an entirely different product.
Another one popular with teenagers is called HouseParty. This supports up to 8 people at a time. However, I don't recommend the use of this as the security and privacy policies are pretty dire.
I believe that Discord also does video chat with up to 10 people.
Snapchat supports up to 16 people I think. WhatsApp up to 4. Facebook Messenger up to 50 (only 6 on-screen at once). Instagram up to 4.
I think that Teamviewer also has video chat though I've not had a chance to look at it as yet.
Please do remember though, if you aren't paying directly, you are probably paying indirectly. Lots of these services may use adverts but also gather far more information about you than is comfortable. That information is sold on to 3rd-parties. It is particularly important to let people know this, especially parents.
At least Zoom is trying to sell you a service and is a little more enterprise focused. Google Hangouts is also a known entity and we already know how they reuse data so most of us are a little more comfortable about that.
